Weave Router alternative

The same idea, with the routing in the open.

Weave Router is a capable drop-in LLM router: swap one base URL, keep your own keys, and requests go to a cheaper model. OmnisRouter works the same way and is built on the same kind of architecture. The reason to pick it is what you can see. OmnisRouter's routing model is open and rebuildable, its savings are measured by a public benchmark you can check yourself, and it is Apache-2.0 rather than a source-available licence. If you searched for an open alternative to Weave Router, this is it.

At a glance

How they compare

DimensionWeave RouterOmnisRouter
LicenceElastic License v2 (source-available)Apache-2.0 (open source)
Routing modelClosed centroidsOpen, ships in the repo, rebuildable from public data
Savings evidenceMarketing figures, no published benchmark to reproduceMeasured by OmnisBench; results published and re-gradable
Drop-in swapYes, base-URL changeYes, base-URL change
Self-host, BYOKYesYes, single process, encrypted keys
FormatsAnthropic, OpenAI, GeminiAnthropic, OpenAI, Gemini
Decision endpoint and receiptsHas a route-preview and analytics exportSame, plus receipts tied to a published, versioned model
Managed pricingNot publishedNot applicable (self-host); any hosted layer later keeps routing open
Fair's fair

Where Weave Router stands

Weave Router is a real product from a funded team, and the core is well built: the endpoint swap is clean, it preserves streaming, tools and vision across providers, it keeps prompt caches warm with session pinning, and it runs BYOK on your own infrastructure. If none of the openness questions below matter to you, it is a reasonable tool. OmnisRouter exists because, for a lot of people, those questions do matter.

The reason to switch

You can check the routing, and the savings

A router that decides where your money goes is asking for trust. OmnisRouter tries to earn it rather than ask for it. The intent-cluster model and policy table are in the repo, and the offline job that builds them is documented, so the same inputs produce the same model. Every decision is stamped with the model version that made it. The coding and maths policy is driven by real numbers from OmnisBench, our companion benchmark, so a claim like "the cheap model is good enough here" is something you can go and re-grade, not a figure on a slide. A closed router cannot offer that, and a source-available licence is not the same as open.

Moving over

Switching is another base-URL change

Because both are drop-in proxies that speak the same wire formats, moving is the same swap you already did once. Point your client at OmnisRouter, add your provider keys, and you are routing. Ask POST /v1/route what it would do with a request before you send it, and read the X-Omnis-* receipt headers on the way back.

# what would it do, and what does it save? no upstream call.
$ curl -s localhost:8080/v1/route -H "authorization: bearer $TOKEN" \
       -d '{"messages":[{"role":"user","content":"Summarize this thread."}]}'
{ "policy_version": "v3-omnisbench-2026-08-20",
  "decision": "ROUTED", "reason": "cheapest_capable",
  "chosen": { "provider": "gemini", "model_id": "gemini-2.5-flash" },
  "est_cost_delta_vs_big_usd": -0.0121 }
Questions

Frequently asked

What is a good open-source alternative to Weave Router?
OmnisRouter. Same drop-in idea, same base-URL swap, same BYOK self-host, but the routing model ships in the repo and rebuilds from public data, the savings are measured by a public benchmark you can re-grade, and it is Apache-2.0 rather than the Elastic License.
How is OmnisRouter different from Weave Router?
The architecture is similar: an in-process embedder plus a cluster scorer, three wire formats, BYOK, a decision endpoint. The differences are that OmnisRouter publishes and lets you rebuild its routing model, backs its coding and maths policy with the OmnisBench benchmark, and uses a fully open Apache-2.0 licence. Weave Router's routing model is closed and it is offered under the source-available Elastic License.
Is OmnisRouter free and self-hostable?
Yes. It runs as a single self-hosted process with an embedded database, you bring your own provider keys, and routing is never paywalled. Apache-2.0.